A method for papermaking white mud to enhance the degradation of waste feathers by Bacillus

Abstract

The invention discloses a method for enhancing the degradation of waste feathers by bacillus using papermaking white mud. Waste feathers and papermaking white mud are added to deionized water, and then a strain of Bacillus subtilis safely used in the field of feed and fertilizer is inoculated for cultivation. A trace amount of papermaking white mud as an inorganic salt component can significantly enhance the ability of microorganisms to degrade waste feathers, saving the cost of degrading waste feathers. At the same time, the reduction and appreciation of both are achieved, and the resource utilization of waste is promoted.

Description

Technical Field

[0001] The invention belongs to the field of resource utilization of livestock and poultry breeding wastes, and specifically relates to a method for enhancing the degradation of waste feathers by bacillus using papermaking white mud. Technical Background

[0002] In recent years, with the high-quality development of my country's economy, people's living standards have continued to improve, and the intensive development of livestock and poultry farming has been rapid; as one of the main by-products in the field of livestock and poultry farming, discarded feathers have a huge annual output. According to statistics, the total annual output of discarded feathers in my country is about four million tons, and its global total annual output reaches tens of millions of tons. Feathers have a high crude protein content (>90%) and are a cheap high-protein resource with broad application prospects in animal feed, plant fertilizers, and biomaterials. However, under the action of rich disulfide bonds, the structure of feathers presents durability and firmness, which can withstand the erosion of microorganisms and biological enzymes, and it is difficult to degrade in the natural state. If improperly handled, it will not only pollute the environment, but also waste protein resources.

[0003] Only by breaking the solid structure of feathers and forming keratin that is easy to use, or soluble and easily absorbed amino acids and oligopeptides, can the high-value resource utilization of discarded feathers be achieved. Conventional physical and chemical methods (such as strong alkali method and puffing method) can quickly destroy the structure of feathers, but will pollute the environment or reduce the nutritional value. In contrast, the use of microorganisms to degrade discarded feathers has the characteristics of being green, safe, and economical, and has attracted widespread attention from feather degradation researchers. In recent years, although the number of microorganisms that degrade feathers has continued to increase, the efficiency of most microorganisms in degrading feathers is not high, and the degradation time needs to be more than 5 days. Only a few microorganisms can degrade feathers in about 2 days. In order to degrade discarded feathers on a large scale, the efficiency of feather degradation needs to be further improved. Microorganisms usually have a better effect on degrading feathers under alkaline conditions. In terms of improving the degradation rate of feathers, current research mainly focuses on improving the enzymatic activity and stability of keratinase by genetic modification. In fact, the process of microbial expression of proteases is greatly affected by environmental factors, and even largely restricts its efficient expression. Therefore, improving the microenvironment of microbial degradation of feathers can regulate the efficient expression of proteases related to feather degradation.

[0004] Studies have shown that calcium ions can bind to the structure of keratinase and increase the activity of keratinase. Papermaking mud contains a large amount of calcium carbonate, as well as a small amount of trace elements such as magnesium and iron, and is highly alkaline. According to statistics, the annual output of papermaking mud in my country is about 17 million tons, accounting for more than half of the world's annual output, which is very likely to cause harm to the ecological environment. Studies have found that papermaking mud can improve the stability of anaerobic fermentation of food waste and the output of pullulan produced by microorganisms. A search of relevant literature found that no research on the microbial degradation of feathers by papermaking mud has been reported. Based on the above characteristics and applications of papermaking mud, papermaking mud has potential applications in the field of feather degradation. While promoting feather degradation, it also broadens the scope of resource application of papermaking mud, which can enhance the dual benefits of waste feathers and papermaking mud in terms of environment and economy. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a method for enhancing the degradation of waste feathers by bacillus using papermaking mud to produce high-calcium amino acids. The method comprises adding papermaking mud to deionized water, adding waste feathers for sterilization, inoculating bacillus for fermentation to produce high-calcium amino acids, and significantly enhancing the ability of bacillus to degrade feathers.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for enhancing the degradation of waste feathers by bacillus using papermaking white mud is provided. Waste feathers and papermaking white mud are added to a culture medium, and then Bacillus subtilis is inoculated for cultivation.

[0008] Preferably, the waste feathers and papermaking mud are added to the culture medium, and the weight fraction includes 1% of waste feathers and 0.05-0.9% of papermaking mud, the pH is a natural value, and the balance is deionized water.

[0009] Preferably, the culture medium is an inorganic salt culture medium, which includes 0.03-0.09% NaCl, KH 2 PO 4 0.02~0.1%、K 2 HPO 4 0.04~0.16%、MgCl 2 6H 2 O 0.005~0.03%, FeSO 4 7H 2 O 0.02-0.16%, pH 8.0-10, and the balance water. More preferably, the amount of papermaking white mud added is 0.05-0.3% by mass, and the amount of waste feathers added is 1% by mass.

[0010] Preferably, the Bacillus subtilis is Bacillus subtilis CICC 10092.

[0011] Preferably, the bacillus is spread on a solid LB medium, statically cultured at 30-37° C. for 15-25 hours to activate the bacillus, and after a single colony is formed, the single colony is picked and placed in a liquid LB medium, and cultured with shaking at 30-37° C. and 180-250 rpm for 12-20 hours to prepare a seed solution, and the seed solution is transferred to an inorganic salt medium or mud-hair medium containing waste feathers and papermaking white mud at a volume ratio of 2-8%, and cultured and degraded at 30-37° C. and 180-250 rpm for 30-45 hours.

[0012] The inorganic salt culture medium includes, by mass fraction, 0.03-0.09% NaCl, KH 2 PO 4 0.02~0.1%、K 2 HPO 4 0.04~0.16%、MgCl 2 6H 2 O 0.005~0.03%, FeSO 4 7H 2 O 0.02~0.16%, pH 8.0~10, the balance is water, sterilize at 115℃ for 20min.

[0013] The mud-hair culture medium comprises, by mass fraction, 1% of discarded feathers and 0-0.7% of papermaking white mud, with a natural pH value and the remainder being deionized water, and is sterilized at 115° C. for 20 minutes.

[0014] Beneficial effects of the present invention:

[0015] (1) A small amount of papermaking mud as an inorganic salt component can significantly enhance the ability of microorganisms to degrade waste feathers, thereby saving the cost of degrading waste feathers.

[0016] (2) The combination of papermaking mud and waste feather degradation can reduce the amount of both wastes and increase their value, providing a new idea for the resource utilization of papermaking mud and environmental protection.

[0017] (3) Microorganisms used as feed and fertilizer are used to convert waste feathers and papermaking mud into soluble high-calcium amino acid solutions, which have the potential to prepare feed and fertilizer, thereby promoting the resource utilization of waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of converting waste feathers and papermaking mud into high-calcium amino acid solution.

[0019] Figure 2 The effect of papermaking mud on the efficiency of Bacillus licheniformis in degrading waste feathers in inorganic salt culture medium.

[0020] Figure 3 The effect of papermaking mud in deionized water on the efficiency of Bacillus licheniformis in degrading waste feathers. Specific embodiments

[0021] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments, but does not constitute any limitation to the present invention.

[0022] This embodiment is described by taking Bacillus licheniformis CICC 10092 suitable for biological feed and fertilizer as an example. The strain was purchased from the China Industrial Microbiological Culture Collection Management Center.

[0023] The present invention uses papermaking mud as an inorganic salt component and provides an alkaline environment to convert waste feathers into a high-calcium amino acid solution through the metabolism of microorganisms. The process is as follows: Figure 1 shown.

[0024] Example 1 Effect of papermaking mud on the degradation of waste feathers by Bacillus licheniformis in a normal inorganic salt environment

[0025] Bacillus licheniformis CICC 10092 used for feed and fertilizer is spread on solid LB medium and cultured at 37°C for 20 hours to form a single colony. The single colony is transferred to liquid LB medium and cultured at 37°C and 200rpm for 16 hours to obtain seed solution. The seed solution is transferred to an inorganic salt medium containing discarded chicken feathers and papermaking mud at a volume ratio of 4%, wherein the content of discarded chicken feathers is 1% by mass, and the amount of papermaking mud added is 0%, 0.05%, 0.1%, 0.3%, 0.5%, and 0.7% by mass, respectively. The culture is carried out at 37°C and 200rpm for 40 hours. The degradation rate of discarded feathers is detected by differential weight method. Figure 2 As shown in the results, with the increase of the amount of papermaking mud added, the degradation rate of discarded chicken feathers first increased and then decreased; when the amount of papermaking mud added was 0.05-0.3%, it reached a maximum of 90.6±1.5%, which was 8.4% higher than the control group (83.6%). This shows that papermaking mud has a positive effect on the degradation of discarded chicken feathers under the condition of containing inorganic salts.

[0026] The inorganic salt medium includes, by mass fraction, 0.05% NaCl, KH 2 PO 4 0.04%、K 2 HPO 4 0.04%, MgCl 2 6H 2 O 0.01%, FeSO 4 7H 2O 0.04%, pH 8.5, the balance is water, sterilized at 115℃ for 20min. Waste feathers and papermaking mud are added as needed.

[0027] Example 2 Effect of papermaking mud alone on the degradation of discarded feathers by Bacillus licheniformis

[0028] Bacillus licheniformis CICC 10092 was inoculated into a deionized water medium (mud-hair medium) containing papermaking white mud, and the addition amount of papermaking white mud was 0%, 0.05%, 0.1%, 0.3%, 0.5%, and 0.7% by mass, respectively. The operation steps were the same as those in Example 1. Figure 3 As shown in the figure, the degradation rate of discarded chicken feathers in the experimental groups with added papermaking mud was not significantly different, reaching 88.2%, which was 54.5% higher than that in the control group (57.1%). At the same time, this effect was higher than the degradation rate of CICC 10092 strain in inorganic salt medium (83.6%, Figure 2 ), and the degradation rate of discarded chicken feathers in an environment containing papermaking mud and inorganic salts is close to that of discarded chicken feathers ( Figure 2 ). This shows that papermaking mud alone can significantly enhance the ability of Bacillus licheniformis CICC 10092 to degrade discarded chicken feathers and obtain a high-calcium amino acid solution. This may be because papermaking mud provides inorganic salt elements, which promotes the growth of microbial cells; it also provides abundant calcium ions, which enhances the expression and secretion of keratinase, thereby improving the degradation efficiency of discarded chicken feathers.

[0029] The mud-hair culture medium comprises, by mass fraction, 1% of discarded feathers and 0-0.7% of papermaking white mud, with a natural pH value and the remainder being deionized water, and is sterilized at 115° C. for 20 minutes.

[0030] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto, and any simple modification, change or equivalent substitution made within the concept and principle of the present invention should be considered to still fall within the protection scope of the present invention.

Claims

1. A method for enhancing the degradation of waste feathers by Bacillus using papermaking white mud, characterized in that: Add waste feathers to the culture medium The raw materials are mixed with cotton wool and papermaking mud, and then inoculated with Bacillus subtilis for cultivation.

2. The method according to claim 1, characterized in that: The waste feathers and papermaking mud are added to the culture medium. Calculated by mass fraction, it includes 1% of waste feathers, 0.05-0.9% of papermaking white mud, the pH value is a natural value, and the balance is deionized water.

3. The method according to claim 2, characterized in that The addition amount of papermaking white mud is 0.05-0.3% by mass, and the addition amount of waste feathers is 1% by mass.

4. The method according to claim 1, characterized in that: The Bacillus subtilis is Bacillus subtilis CICC10092.

5. The method according to claim 1, characterized in that Spread the Bacillus in solid LB medium and culture it at 30-37°C for 15-25 hours to activate the Bacillus. After a single colony is formed, pick a single colony and place it in liquid LB medium. The culture medium is shaken and cultured at 30-37°C and 180-250 rpm for 12-20 hours to prepare a seed solution, which is transferred to an inorganic salt culture medium or mud-hair culture medium containing discarded feathers and papermaking white mud at a volume ratio of 2-8%. The culture and degradation were carried out at 30-37°C and 180-250 rpm for 30-45 h.

6. The method according to claim 5, characterized in that The inorganic salt culture medium includes, by mass fraction, 0.03-0.09% NaCl, 0.02-0.1% KH2PO4, 0.04-0.16% K2HPO4, 0.005-0.03% MgCl2·6H2O, 0.02-0.16% FeSO4·7H2O, 0.05-0.3% papermaking white mud, 1% waste feathers, pH 8.0-10, and the balance is water. The culture medium is sterilized at 115°C for 20 minutes.

7. The method according to claim 5, characterized in that The mud-hair culture medium comprises, by mass fraction, 1% of discarded feathers and 0-0.7% of papermaking white mud, with a natural pH value and the remainder being deionized water, and is sterilized at 115° C. for 20 minutes.

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